前言：之前博客里面提到本公司为物联网项目。项目中使用mqtt+kafka进行与设备端的通讯，之前的协议格式为json格式，现在改成字节数组byte[]格式进行通信。

• 报错信息如下

Can't convert value of class [B to class org.apache.kafka.common.serialization.StringSerializer specified in value.serializer

Field kafkaTemplateByte in com.hiss.producer.KafkaNewProducer required a bean of type 'org.springframework.kafka.core.KafkaTemplate' that could not be found.
- Bean method 'kafkaTemplate' in 'KafkaAutoConfiguration' not loaded because @ConditionalOnMissingBean (types: org.springframework.kafka.core.KafkaTemplate; SearchStrategy: all) found bean 'kafkaTemplate'


Action:
Consider revisiting the conditions above or defining a bean of type 'org.springframework.kafka.core.KafkaTemplate' in your configuration.

• 分析原因
  之前声明KafkaTemplate时候value值为String，后续改为byte[]时候，未将KafkaTemplate的value类型改为byte[]类型。

• 解决办法

 public KafkaTemplate<String, byte[]> kafkaTemplateByte() {
    	return new KafkaTemplate<String,byte[]>(producerFactoryByte());
    }